Vortex formation of spherical self-propelled particles around a circular obstacle
Vortex formation of spherical self-propelled particles around a circular obstacle
复制标题
球形自驱动粒子围绕圆形障碍物的涡流形成
DOI：
10.1039/d0sm00277a
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发表时间：
2020
期刊：
影响因子：
3.4
通讯作者：
Chen Kang
中科院分区：
文献类型：
--
作者：
Pan Jun-xing;Wei Hua;Qi Mei-jiao;Wang Hui-fang;Zhang Jin-jun;Tian Wen-de;Chen Kang
涡旋是有源系统中常见的棘轮现象。空间对称性通常通过引入不对称形状或在流体动力相互作用或其他对齐效应的存在下由集体运动自发地破坏。出乎意料的是，我们通过模拟观察到，在最简单的圆形障碍物模型中，一个漩涡的形成浸没在球形自推进粒子的浴缸中。该模型不考虑上述对称破缺因素。只有粒子活性高，即持续时间长，才会形成涡旋。障碍物尺寸也是一个关键因素，涡流只在有限的障碍物尺寸范围内形成。涡旋的维持源于围绕障碍物旋转的粒子簇在接受进入的粒子时基于其推进方向的偏差。我们的研究结果对活性物质中的自发对称破缺和棘轮现象提供了新的认识和见解。
A vortex is a common ratchet phenomenon in active systems. The spatial symmetry is usually broken by introducing asymmetric shapes or spontaneously by collective motion in the presence of hydrodynamic interactions or other alignment effects. Unexpectedly, we observe, by simulations, the formation of a vortex in the simplest model of a circular obstacle immersed in a bath of spherical self-propelled particles. No symmetry-breaking factors mentioned above are included in this model. The vortex forms only when the particle activity is high, i.e. large persistence. The obstacle size is also a key factor and the vortex only forms in a limited range of obstacle sizes. The sustainment of the vortex originates from the bias of the rotating particle cluster around the obstacle in accepting the incoming particles based on their propelling directions. Our results provide new understanding of and insights into the spontaneous symmetry-breaking and ratchet phenomena in active matter.